The present invention relates to a long felt but unsatisfied need for improvement in use of high security deadbolt devices. More particularly, the invention herein describes a structure and method for association with conventional single or double cylinder deadbolts (two keys) that permit a person on the inside to release or reengage the deadbolt by use of a thumb lug.
Deadbolt assemblies including single and dual cylinder deadbolt mechanisms are well known security adjuncts. Single cylinder deadbolt mechanisms are normally key-operated from the outer side of the door to translate the deadbolt from the lock recess, with a thumb turn provided on the inner side of the door.
Double cylinder deadbolt mechanisms do not have the interiorly disposed thumb-turn associated with the single cylinder assemblies and rely, instead, on insertion and rotation of a key to translate the bolt. Double cylinder deadbolts are prohibited in certain jurisdictions as a result of the hazard created from the inability of an authorized person to escape from the interior of a structure in emergency events such as a structural fire. Such issues are specifically addressed in the patent literature such as in Oliver, U.S. Pat. No. 4,315,420, which discloses a retained key, double cylinder deadbolt assembly. The patent literature also contains some unusual solutions to retrofit and essentially disable existing dual cylinder deadbolts where such locks have been outlawed subsequent to installation. One such device is described in U.S. Pat. No. 5,140,843, which, in effect, clads a key located in the interior cylinder of a dual cylinder lock within plates to convert the key into a permanent thumb lug but correspondingly eliminate the security benefit provided by a double cylinder deadbolt.
A double cylinder deadbolt offer greater security on doors, particularly those incorporating glass panels, because it requires the insertion of a key for operation to unlock a latched deadbolt even from the inside. This provides a security advantage by preventing egress by unauthorized persons carrying stolen material through the door, e.g., preventing large items from being removed through the locked door during a robbery. This security advantage, however, turns into a disadvantage in the case of an emergency such as a fire. In such a case, a latched dual cylinder deadbolt may delay egress and, thus, prevent escape in the event of an emergency. This risk is magnified in the case of an elderly, infirmed, or physically disabled individual. To address this problem, conventional wisdom recommends that the owner maintain the interior key in the interior cylinder (thereby defeating the dual cylinder function) or locate a hidden key proximate to the door for use in emergencies. Obviously, security advantages provided by a double cylinder deadbolt are compromised in such a case.
In view of the less than universal acceptance of dual cylinder deadbolt assemblies, most installers follow regulations and substitute single cylinder deadbolts in favor of dual cylinder deadbolts. As noted, single cylinder deadbolts avoid obstructing easy egress from a premise during a fire or other emergency. However, that advantage requires sacrifice of protection on doors or where the lock is proximate to a glass panel or a door is formed of glass.
While some of the foregoing difficulties have been referred to in the patent literature, no practical solution has been offered to overcome problems associated with dual cylinder deadbolts. None of the structures disclosed in the patent literature contemplate the effective preservation of security of a double cylinder deadbolt lock while providing a plurality of user selective egress modes based on simple physical manipulation.
What is needed in the art of authorized manipulation of deadbolts particularly facilitating escape in the case of a true emergency, is a simple, easily operated, effective, universal, user selective egress mode system and method that may be integral with new manufacture or retrofittable conversion.
It is an object of this invention to provide a cylinder type deadbolt assembly overcoming the problems with the prior art.
It is another object of this invention to provide a deadbolt adjunct that is at once secure, effective, inexpensive and easily incorporated on newly manufactured deadbolt products or retrofittable to existing products.
It is an object of the invention to provide a rotatable digit driven lug that releases a deadbolt from the locked position.
It is a further object of this invention to provide an adapter for simple convertibility of conventional double cylinder deadbolt assemblies to meet the objective of the invention to reduce effort required for authorized release of the deadbolt in the event authorized egress is desired.
A further object of this invention is to provide an assembly for adapting a deadbolt thumb latch to double cylinder deadbolts.
Still a further object of this invention is to provide a method for emergency deadbolt release.
A further object of this invention is to provide an apparatus and method permitting conversion in a minimum of time of conventional double cylinder deadbolt structures to an egress facilitating structure without compromising security.
These and other objects of the invention are satisfied by a combination of
a dual cylinder dead bolt and a dual cylinder dead bolt adjunct permitting selective keyless operation.
Still other objects of the invention are provided by a method of opening a door having a dual cylinder deadbolt with a translatable deadbolt and a dual cylinder deadbolt adjunct of the type depicted and described herein, including the steps of:
inserting an authorized opening means such as a key into the deadbolt;
detenting a manipulation means such as a physical thumb latch into an engaging position to transfer motion from the manipulation means to the deadbolt latch;
removing the opening means; and
moving the manipulation means to translate the deadbolt.
The invention herein, referred to as DCDA (double cylinder deadbolt adjunct), in practice, allows a user to select one of three operative modes of a double cylinder deadbolt. In order for a user to select the mode of operation, the user must be authorized, e.g., be in possession of a key. Only with the key inserted can the user change the mode of the actuator operation.
The user may select in one mode to retain the full operability of the double cylinder deadbolt or may select to rely on a single cylinder modality for egress. The DCDA permits the user to select and change the functionality at any time, so long as the user inserts the proper key/key card, electronic key/remote, etc. Where the user selects to set the adjunct by manipulation of the actuator (a collar, lever or button, etc.) to a single cylinder mode, the dual cylinder deadbolt, in essence is converted to a single cylinder deadbolt where the deadbolt may be retracted or engaged by physical manipulation of the actuator. Being operatively disposed on the inside of the door, the actuator is typically associated with the periphery of the deadbolt""s interior lock portion. Also, when radially depressed, the DCDA can be rendered non-functional which leaves the door unlocked unless the proper key is inserted and the mode changed by the user.
Thus, the invention provides for three basic operative modes; double cylinder, single cylinder, and DCDA disabled mode.
The outer/exterior cylinder controls the function of the DCDA. Upon exiting a premises, an authorized user may want to engage the deadbolt but allow for easy egress by a person on the inside who may unlocked the deadbolt without use of the key (e.g. single cylinder mode). Thus, any occupant may retain the enhanced security provided by a deadbolt while permitting others properly on the premises to exit the door in the case of an emergency. On the other hand, if the person wishes to employ the deadbolt in its fully secure mode, by setting the DCDA to its double cylinder operative mode prevents unlocking of the door without the key.
Preferably the DCDA includes an indicator, to indicate the status of the associated deadbolt. The indictor may be mechanical or electronic and will clearly indicate the current operative mode of the deadbolt, e.g., single cylinder or double cylinder. Preferably, the indicator also shows whether the deadbolt is locked or unlocked.
The invention herein is useful in deadbolt security involving a wide range of particular structures, either new or retrofit. In keeping with the objectives, the invention is both simple and easily deployable. Based on its capabilities, the invention herein is readily operational in conjunction with virtually any double cylinder deadbolt structure while providing the necessary manipulability of a thumb turn by an authorized individual from the interior side.
In part, owing to its ability to provide easy unlatching of a deadbolt, the invention reduces the hazard of injury to the person from a hostile setting from the interior, e.g. fire, or attack. Consequently, the invention is readily adaptable and effective at minimal cost and installation.
As used herein in additional to conventional dictionary definitions, the following may be used in connections with the associated terms.
Single Cylinder Deadbolt: A deadbolt lock which operates with manipulable element (typically a thumb turn) on the interior and a keyed cylinder on the outside of the door. A single cylinder deadbolt is generally used on a door that does not include an obvious weakness, e.g., glass panels.
Double Cylinder Deadbolt: A deadbolt lock which operates with a keyed cylinder on both sides of the door. A double cylinder deadbolt is generally used on a door that has glass on or around it. Thereby preventing someone from breaking the glass and reaching inside to open the doorxcx9cthere been a single cylinder deadbolt installed.
The foregoing and other objects and advantages will appear from the description to follow. In short, the invention herein, is directed particularly to a convertible, manually operable double cylinder deadbolt adjunct providing for selectivity of three operative modes. In the description, reference is made to the accompanying drawing which forms a part hereof, and in which is shown by way of illustration a specific embodiment in which the invention may be practiced. This embodiment will be described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is best defined by the appended claims.